Quiet metal can



Oct. 20, 1970 J, H. BOTSFORD 3,534,882

QUIET METAL CAN Filed March 25, 1969 l NV E N TOR F (5 James bf Bo/sforaUnited States Patent 01 3,534,882 Patented Oct. 20, 1970 3,534,882 QUIETMETAL CAN James H. Botsford, Bethlehem, Pa., assignor to Bethlehem SteelCorporation, a corporation of Delaware Continuation-impart ofapplication Ser. No. 688,094, Dec. 5, 1967. This application Mar. 25,1969, Ser. No. 814,516

Int. Cl. B65d 25/00 US. Cl. 220-1 22 Claims ABSTRACT OF THE DISCLOSUREVibration, and resulting noise, generated by a metal garbage can iseffectively reduced with sandwich of felt between vibration-proneportions of can and metal member. Straps of felt and metal are mountedaround can body, around flange of lid, across lid offset from lidcenter, and across bottom offset from botton center. Discs of felt andmetal may be mounted to center of can bottom. Resilient feet are mountedaround bottom flange of can body. Handles frictionally engage stirrupsto prevent rattling.

CROSS-REFERENCES TO RELATED APPLICATIONS This application is acontinuation-in-part of application Ser. No. 688,094, now abondonedfiled Dec. 5, 1967.

BACKGROUND OF THE INVENTION This invention relates broadly to means forreducing noise generated by cans and lids during the handling thereof.More specifically, this invention relates to the application ofvibration-damping mechanism to various surfaces of a can and lid toreduce noise.

The clang and rattle of the lowly garbage can has with somejustification been compared to the sound of a struck gong or the clashof cymbals. In a large city, the tintinnabulation of hundreds ofthousands, indeed millions, of garbage cans and lids being brought intoviolent contact wtih each other and with concrete pavement, when lvingly handled with the well-known consideration of the garbage crew forthe slumbering householder in the still of the night, can have adevastating effect on the peace and quiet, if not sanity, of thecommunity. Despite the evident need for a rugged and truly quiet garbagecan, the prior art simply has offered no solution to this problem. It istrue that plastic garbage cans and lids are available, and that they arequieter than the traditional galvanized steel cans. However, plasticgarbage cans and lids are quite expensive, will not stand up under roughhandling, and are particularly susceptible to breakage in cold weather.

SUMMARY OF THE INVENTION One of the objects of this invention is toprovide an improved metal can and lid therefor.

Another of the objects of this invention is to provide a metallicgarbage can and lid therefor which will generate substantially lessnoise in handling than conventional metallic garbage cans.

Yet another object of this invention is to provide a metallic garbagecan and lid therefor which will generate a low level of noise inhandling comparable to a plastic garbage can and lid, but which will beconsiderably more rugged under all conditions of use than the plasticgarbage can and lid therefor.

Other and further objects of this invention will become apparent duringthe course of the following description and by reference to theaccompanying drawings and the appended claims.

Is has been discovered that the foregoing objects can be attained byapplying means to various portions of the can and lid to damp or absorbnoise-producing vibrations. Specifically, a constrained layer treatment,discussed generally in Noise Reduction Manual by P. H. Geiger, 1953, atpages -96, is applied to specific areas of greatest vibration on the canbody and on the lid.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 represents a view in elevationof the garbage can constituting the present invention, showing one formof lid therefor.

FIG. 2 represents a view in plan of the lid shown in FIG. 1.

FIG. 3 represents an enlarged medial fragmented section in elevation ofthe garbage can.

FIG. 4 represents an upward view of the bottom of the garbage can ofFIG. 1, showing one form of vibration damper applied to one form of canbottom.

FIG. 5 represents an enlarged vertical section of a portion of the canbottom shown in FIG. 4, taken along the line 5-5 of FIG. 4.

FIG. 6 represents a view in plan of another form of lid.

FIG. 7 represents an upward view of the bottom of a garbage can, showinganother form of vibration damper applied to another form of can bottom.

FIG. 8 represents an enlarged vertical section of a portion of the canbottom shown in FIG. 7, taken along the line 8-2 of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Garbage can 1 is seen ascomprising body 2, having a bottom 3, and a lid 4 of metallicconstruction, e.g., galvanized steel.

The intensity of the vibrations in each of these parts variesconsiderably over the area thereof. For the sake of economy, it isdesirable to apply the aforementioned constrained layer treatmentprimarily only to those areas where the intensity of vibrations isgreatest. Such areas can be determined from a physical analysis of themodes of vibration of each part. This analysis may comprise placing thepart to be analyzed near a loudspeaker con nected to a variablefrequency oscillator, and varying the frequency until the lowestmechanical resonant frequency of the part is found. At this resonance, anoticeable increase in the volume of the sound occurs. The pattern ofvibration of the part at this resonance may then be determined by movinga metal object, e.g., the blade of a screwdriver, over the surface ofthe part while exerting light pressure there against with said blade. Asthe blade is moved away from the nodes a chattering becomes audible, theintensity thereof reaching a maximum at the antinodes.

This procedure is then repeated for the three or four modes of vibrationnext higher in frequency to find the areas of maximum vibrationintensity for these modes.

A constrained layer of vibration damping material is then applied to thepart so as to cover these areas of higher intensity vibrationseffectively. It is essential that said material be applied in such amanner that the basic pattern of vibration of the part is not disturbed;otherwise, the nodes and antinodes in the part will shift and thevibration damping treatment is likely to be ineffective. More complexmodes having higher frequencies will automatically be damped by thisplacement.

The above-described vibration analysis is then repeated whereby theeffectiveness of the constrained layer may be determined. By successiveapproximation, the optimum placement of the constrained layer can bedetermined.

The can body 2 shown in FIG. 1 was 24 inches high and was characterizedby maximum vibrations approximately 9 inches below the top thereof. Abelt of vibration damping material, having a width of about one inch,was therefore placed about said body so as to be circumferentiallydisposed about 9 inches below the top thereof. The belt 5 was maintainedin position about the can body 2 by means of a metallic strap 6. Saidstrap 6 engaged substantially the entire outer circumferential surfaceof the belt 5, and cooperated with the body 2 to constrain the belt 5.

Strap 6 may be riveted or bolted to body 2 through the belt 5 or throughholidays in the belt 5, or may be spot welled to body 2 through holidaysin the belt 5, or may simply be formed as a closed hoop with ends lappedand secured to each other under such compression as to providesufficient friction between belt 5, body 2 and strap 6 as to maintainthe position of belt 5 and strap 6 relative to body 2. v

While all materials absorb vibrations to some extent, the term vibrationdamping material as used herein is meant to include only those materialshaving a decay rate of at least 1 db./sec., as measured by the standardThick Plate Test. For example, asphalt saturated felts, especially thosehaving indentations therein, are suitable for the belt 5. Armstrong FeltSpecification No. 415, described in the Armstrong publication Felt andFiber Products for the Industrial Designer, published December 1965, hasa decay rate of 3.0 db./sec. and is ideally adapted for use as the belt5.

By constraining the belt 5 with the strap 6, the decay rate can beincreased from about 3.0 db./sec. to over 100 db./ sec.

One form of can bottom 3, as shown in FIG. 4, is conventially stamped toprovide a number of concentric circular stiffening rings 7 and radialstiffening legs 8. Vibrations, and hence noise, generated by this formof bottom are greatest at the center thereof, and are damped andlessened by means of a constrained circular plate 9 of vibration dampingmaterial such as indented asphalt saturated felt. Said felt is fastenedto the center of bottom 3, as by means of adhesive, with a constrainingmetallic circular plate 10 engaging substantially the entire outersurface of plate 9, as by means of adhesive, and cooperating with thebottom 3 to constrain the plate 9. In a specific example of practice, ithas been found that, when circular plates 9 and 10 having a diameter of6 inches are mounted to the center of a bottom 3 having a conventionaldiameter of inches, vibrations, and resulting noise, generated by thebottom 3, are most effectively reduced.

Conventionally, the bottom 3 of a garbage can is mounted to the body 2some distance above the bottom of body 2, so that body 2 projects as acircular flange 11 below bottom 3. Typically, the flange 11 may projectapproximately inch below bottom 3. A number of feet 12, made ofresilient material such as rubber, plastic or the like, are mounted inequispaced relation around flange 11, and are held thereto by frictionalengagement, as shown in FIG. 3, although other means such as screws,rivets, adhesive, etc, may be employed. Feet 12 prevent the metallicflange 11 from striking concrete pavements and generating noise. Inplace of several feet 12 as shown, a continuous rubber or plastic lipextending around the circumference of flange 11 may be employed.

Handles 13 are mounted in stirrups 14 suitably secured to body 2. Meansis provided to cause the handles 13 to bind in stirrups 14, thereby toeliminate the rattling generated by loose handles. In FIG. 3, a piece 15of resilient material, such as rubber tubing or the like, is wedged instirrup 14 between handle 13 and body 2, this arrangement providingsufficient friction binding the handle 13 within the stirrup 14, and yetpermitting handle 13 to be rotated within stirrup 14 as required. Othermeans for causing the handle 13 to bind in stirrup 14 will occur to thereader, such as employing a plastic coated handle 13, or a spring withinthe stirrup exerting friction against the handle 13, or a toggle portionon the handle 13 engaging the stirrup and holding the handle in one ofseveral pre-selected positions.

Lid 4, having the customary handle 16 and stamped with the customarystiffening rings 17, is provided with a circumscribing band 18 ofvibration damping material, such as indented asphalt saturated felt.Said felt is maintained in position around lid 4 by means of a metalliccircumscribing band 19, said band 19 engaging substantially the entireouter surface of the band 18 and cooperating with the flange of the lid4 to constrain the band 18. Band 19 may be riveted or bolted to lid 4through the band 18 or through holidays in the band 18, or may be spotwelded to lid 4 through holidays in the band 18, or may simply be formedas a closed loop with ends lapped and secured to each other under suchcompression as to provide sufficient friction between bands 18 and 19damps noise-producing vibrations generated by the relative to lid 4.Extending across the top of lid 4 is a strap 20 of vibration dampingmaterial, such as indented asphalt saturated felt. Said felt ismaintained in position by means of metallic strap 21, the ends of thelatter being tucked between lid 4 and bands 18 and 19 as shown. Thestrap 21 engages substantially the entire outer surface of strap 20, andcooperates with the top of the lid 4 to constrain the strap 20. Strap 20may be cemented to lid 4, and strap 21 cemented to strap 20, by means ofsuitable adhesives, or rivets or bolts employed as hereinbeforedescribed. The assembly of bands 18 and 19 damps noise-producingvibrations generated by the flange of lid 4, and straps 20 and 21 dampnoiseproducing vibrations generated by the face of lid 4. The positionof straps 20 and 21 on lid 4 is quite important, as this position,offset from the center of lid 4, straddles an area in whichsubstantially all modes of vibration of the face of the lid 4 arepresent. In other words, placing the vibrationdamping arrangement insuch offset position effectively damps substantially all of thevibration modes generated by the face of lid 4. In a specific example ofpractice, it has been found that, when straps 20 and 21, having a widthof 1 inch, are mounted to a lid having a conven tional diameter of 18inches with the center of the straps 20 and 21 offset 2% inches from thecenter of the lid, vibrations, and resulting noise, generated by the lidare most effectively reduced.

A somewhat modified form of vibration damping arrangement applied to theface of lid 4 is shown in FIG. 6. Straps 2t and 21 are not tuckedbetween lid 4 and bands 18 or 19 as shown in FIG. 2, but rather stopshort of the perimeter of lid 4-. Handle 16 is suitably mounted to strap21.

Another form of can bottom 3, as shown in FIG. 7, is conventionallystamped to provide a number of concentric circular stiffening rings 7,without the stiffening legs shown in FIG. 4. Vibrations, and hencenoise, generated by this form of bottom 3 are damped and lessened bymeans of a strap 22 of vibration damping materials such as indentedasphalt saturated felt. A metallic strap 23 engages substantially theentire outer surface of the strap 22 and cooperates with the bottom 3 toconstrain the strap 22. The said straps 22 and 23 are fastened to canbottom 3 in a manner similar to that herein disclosed for straps 20 and21. The position of straps 22 and 23 on can bottom 3 is quite important,as this position, olfset from the center of bottom 3, straddles an areain which substantially all modes of vibration of the bottom 3 arepresent. In other words, placing the vibration damping arrangement insuch offset position elfectively damps substantially all of thevibration modes generated by can bottom 3. In a specific example ofpractice, it has been found that when straps 22 and 23, having a widthof 1 inch, are mounted to a can bottom having a conventional diameter of15 inches, with the center of the straps 22 and 23 offset 3% inches fromthe center of the can bottom, vibrations, and resulting noise, generatedby the can bottom are most effectively reduced.

Straps 22 and 23 may be used on the form of can bottom shown in FIG. 4,in place of plates '9 and 10.

I claim:

1. A receptacle comprising:

(a) a metallic body,

(b) a layer of vibration damping material peripherally engagingsubstantially the entire periphery of said body approximately at thearea of greatest vibration thereof,

(c) means engaging substantially the entire outer surface of said layer,cooperating with saidbody to constrain said layer.

2. An article as in claim 1, in which means (b) and means (c) aredisposed on the upper portion of said body.

3. An article as in claim 1, further comprising:

(d) a stirrup mounted to said body,

(e) handle means having a portion extending through and frictionallyengaging said stirrup.

4. An article as in claim 1, in which said body is substantiallycylindrical, further comprising:

(d) a metallic bottom mounted to the lower portion of said body andclosing the bottom of said receptacle,

(e) a layer of vibration damping material engaging said bottomapproximately at the area of greatest vibration thereof,

(f) means, engaging substantially the entire outer surface of means (e),cooperating with said bottom to constrain means (e).

5. An article as in claim 4, in which means (e) and means (f) comprisediscs located concentrically to the bottom.

6. An article as in claim 4, in which means (e) and means (f) comprisestraps located eccentrically to the bottom.

7. An article as in claim 4, further comprising:

(g) a metallic lid adapted to cover the upper end of said receptacle,

(h) a layer of virbation damping material engaging said lid at an areain which substantially all modes of vibration of the face of said lidare present,

(i) means, engaging substantially the entire outer surface of means (h),cooperating with said lid to constrain means (h).

8. An article as in claim 7, in which means (h) and means (i) comprisestraps located eccentrically to the lid.

9. An article as in claim 8, in which a handle is mounted to saidstraps.

10. An article as in claim 7, in which said lid is provided with acircumferential flange, and a constrained layer of vibration dampingmaterial extends around the circumference of the flange of the lid.

11. An article as in claim 10, in which means (h) and means (i) comprisestraps eccentrically engaging the face of said lid.

12. A metallic circular lid for a receptacle, said lid comprrsmg:

(a) a face portion,

(b) a circumferential flange extending around said face portion,

(c) a layer of vibration damping material engaging said lid,

(d) means, engaging substantially the entire outer surface of means (c),cooperating with said lid to constrain means (c).

13. An article as in claim 12, in which means (c) and means (d) comprisestraps located eccentrically to the face of the lid.

14. An' article as in claim 13, in which a handle is mounted to saidstraps.

15. An article as in claim 12, in which means (c) and means (d) comprisestraps extending around the circumference of the flange of the lid.

16. An article as in claim 15, further comprising:

(e) a strap of vibration damping material eccentrically engaging theface of said lid,

(f) means, engaging substantially the entire outer surface of means (e),cooperating with said lid to constrain means (e).

17. A receptacle comprising:

(a) a metallic substantially cylindrical body,

(b) a metallic bottom mounted to the lower portion of said body andclosing the bottom of said receptacle,

(c) a layer of vibration damping material engaging said bottom,

(d) means, engaging substantially the entire outer surface of means (c),cooperating with said bottom to constrain means (0).

18. An article as in claim 17, in which means (c) and means (d) comprisediscs located concentrically to the bottom.

19. An article as in claim 17, in which means (c) and means (d) comprisestraps located eccentrically to the bottom.

20. A receptacle comprising:

(a) a metallic substantially cylindrical body,

(b) a belt of vibration damping material extending around thecircumference of said body on the upper portion of said body on theoutside of said body,

(0) a metallic strap extending around the outside of and coextensivewith said belt, said strap constraining said belt and maintaining saidbelt in contact with said body,

(d) a stirrup mounted to said body,

(e) handle means having a portion extending through and frictionallyengaging said stirrup,

(f) a metallic bottom mounted to the lower portion of said body andclosing the bottom of said receptacle, said body extending below saidbottom in the form of a circular flange,

(g) resilient means mounted to said flange and adapted to support saidreceptacle,

(h) a layer of vibration damping material engaging the underside of saidbottom,

(i) means coextensive with and engaging the underside of means (h) forconstraining means (h) and maintaining means (h) in contact with saidbottom,

(i) a metallic lid adapted to cover the upper end of said receptacle,said lid having a face and a circircumferential flange of said lid,

(k) a strap of vibration damping material extending around the outsideof said circumferential flange of the lid,

(1) a metallic strap coextensive with and engaging the outside of means(k) for constraining means (k) and maintaining means (k) in contact withsaid circumferential flange of said lid,

(m) a strap of vibration damping material located eccentrically to andextending across the upper surface of the face of said lid,

(11) a metallic strap coextensive With and engaging the upper surface ofmeans (In) for constraining means (m) and maintaining means (m) incontact with the face of said lid.

21. An article as in claim 20, in which means (h) and means (i) comprisediscs located concentrically to the bottom.

22. An article as in claim 20, in which means (h) and means (i) comprisestraps located eccentrically to the bottom.

12/1927 Rosenberg 2207l 9/1939 Hanrahan 220-7l FOREIGN PATENTS 8/1935Great Britain.

RAPHAEL H. SCHWARTZ, Primary Examiner US Cl. X.;R.

